I believe the problem your having stems from a bug in which you change the host and url changes but making a change to the port will not change the url.

Run this...

Code:

zmprov ms runwired.net zimbraMtaAuthHost runwired.net

Then this...

Code:

zmprov gs runwired.net | grep Auth

Then show the output again and check if you can send mail.

If that doesn't work check the settings in the Admin console under "Global Settings" and "MTA" for the Webmail MTA hostname. Then check under "Servers" and the "MTA" tab and see if Webmail MTA hostname is the same there also.